The summary of differential virulence system of Actinomyces viscosus T14V and T14AV offers a unique opportunity to determine what macromolecular components of the resident plaque microbiota are operative in either immune or non-immune based mechanisms of periodonal pathology. The studies supported in this proposal involve purification of high molecular weight antigens from the cell surfaces of these organisms utilizing biological correlates of pathology to identify the important antigens. At the same time, studies are being carried out to examine the environmental conditions that influence the quantity of relative antigens produced by the cell and the conditions that result in release of the antigen into the surrounding environment. In addition, the antigens are being utilized to develop an experimental mouse model to evaluate the mechanisms involved in periodontal pathology.